This invention relates to mattress making machinery and in particular to a tape edge closing machine.
It is well known to close a mattress by sewing along its top edge thereby joining the edge of the panel to the edge of the border boxing with the interposition of a reinforcing tape. As the panel and the border boxing are mutually at right angles the general practice has been to locate the mattress on a horizontal table and to incline the sewing head at an acute angle thereto. The optimum angle is 45.degree. but in practice it has been found possible to close a mattress satisfactorily within a range of angles above and below 45.degree.. Generally, the sewing head is driven around the periphery of the table and very considerable skill is required by an operator who must simultaneously manually pull together the edges to be sewn and at the same time jointly pull these edges into a tape binder to be embraced by reinforcing tape and sewn by the sewing head. This operation involves the operator in bending sideways over the mattress, pulling the material of the panel towards him with an elbow, walking backwards in advance of the sewing head and generally controlling the speed of movement of the sewing head with his knee.
In recent years the construction of mattresses has become increasingly more sophisticated resulting in their being firmer particularly at their edges so making the operator's task even more difficult.
Numerous attempts have been made to improve the basic machine outlined above.
For example, various modifications have been proposed to the mattress supporting table so as to compress the mattress in a direction towards the edge being sewn. This relieves the operator of much of the strain of pulling the panel material towards him with his elbow.
Machines have also been produced in which the sewing head is mounted on a carriage also capable of carrying the operator with the intention of reducing the fatigue involved in constantly walking backwards and also enabling the speed of the carriage to be controlled by a foot pedal instead of by the operator's knee. However, when the carriage moves around the corner of the mattress the operator is inevitably moved away from this corner preventing him from bending closely over the top of the material being sewn, which is necessary for satisfactory mattress closing and in consequence such machines have been generally discontinued.
There is also being produced a machine in which the horizontal mattress table revolves about a vertical axis with the operator seated on a platform carrying an inclined sewing head, the platform being arranged to move through a quarter turn independently of the table as the latter moves a corner of the mattress past the sewing head. In this arrangement the mattress is also compressed from top to bottom and the sewing head arranged to float inwardly and outwardly of the mattress periphery. Compression of the mattress results in production of slack in the material of the panel and of the box border being sewn and in the floating movement of the sewing head readily permitted sewing of the long and short sides of a rectangular mattress.
While this was satisfactory for a single width and length of mattress it would not satisfactorily accommodate the kind of tolerances in panel cutting that must be accepted and again it has been discontinued.
The difficulties set out above and the various attempts made to design machines to overcome them indicate that operators of such machines prefer to be able to move about and not remain seated at a station fixed relative to the sewing head. In the manufacture of mattresses the standards of material cutting and assembly are comparatively low and result in tape edge operators being expected to be able to join together two edges of differing length. The ability to gain or lose material either in the panel or the box separates the skilled from the unskilled operator and in order to exercise maximum skill the operator needs to be able to move about and adjust the materials while sewing.